Vapor generators or boilers for water in which catalyst elements are disposed vertically in the interior of the thermally insulated housing and have the space between the catalyst elements occupied by tubes conducting the liquid to be vaporized from the bottom to the top are known, for example, from U.S. Pat. No. 3,908,602 issued Sept. 30, 1975 to me jointly with Andre Gabriel Hoss. The tube arrays in this patented system are constituted by planar bundles of vertical tubes which are fed from below by common supply tubes or manifolds and are provided, at their tops, with common collectors.
To block the direct radiation from one catalyst heating panel upon another, through the interstices between the tubes of a planar array, it was found to be necessary to provide shields in the form of an array of vanes so as to form a wall free from interstices between the catalyst panels. The walls between pairs of juxtaposed or confronting, spaced-apart catalyst panels, prevent direct radiation from one catalyst panel on the other.
U.S. Pat. No. 3,952,707, issued to me on Apr. 27, 1976, discloses another arrangement, different from the first, for carrying out catalyst combustion of a hydrocarbon and heating of a fluid thereby without direct radiation of heat from one catalyst panel onto the other. In this arrangement the space between the two catalyst elements is occupied by a vertical casing of small thickness which communicates with a lower fluid-supply tube and with an upper collector duct. The casing thus forms a hollow partition or shield, completely free from interstices and continuous between the catalyst element.
For maximum utilization of the thermal output of the device other casings of this type can be disposed outwardly of the catalyst elements and at the top of the generator so as to form outer walls and the roof thereof.
These systems have proved to be highly successful in preventing the direct radiation phenomenon described above and exploiting to a considerable extent the thermal energy of the catalyst agents.